(-8.25x^2)+(66x)=0

Solution for (-8.25x^2)+(66x)=0 equation:

(-8.25x^2)+(66x)=0

We get rid of parentheses

-8.25x^2+66x=0

a = -8.25; b = 66; c = 0;
Δ = b2-4ac
Δ = 662-4·(-8.25)·0
Δ = 4356
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4356}=66$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(66)-66}{2*-8.25}=\frac{-132}{-16.5}
=+8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(66)+66}{2*-8.25}=\frac{0}{-16.5}
=0
$